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3.5
weak
EARTHQUAKE DETAILS

M3.5 earthquake · 2 km North-East of Laino Castello (CS)

6 years ago · 21 Jun 2020, 22:04

A weak earthquake, felt by some of the population. Being deep, it is felt less at the surface.

No. 5 of the month in ItalyStronger than 99% of Italian events in the past yearThe strongest of the past 12 months within 50 km

Where

2 km North-East of Laino CastelloEarthquakes in the province of CosenzaEarthquakes in Calabria

How far away could it be felt?

A quake this small is usually not felt by people: only seismographs record it.

Statistical estimate from the Italian intensity attenuation model (INGV): actual perception depends on geology, buildings and depth. Very shallow events can be felt locally even below the threshold.

Earthquake map

6 events
Magnitude:lightweakmoderatestrong

The energy released

How much energy this quake unleashed, translated into everyday comparisons.

2.7tof TNT equivalent
11 lightning bolts
M3
×5.6 the energy of a magnitude 3 earthquake
M3this quakeM5

Each extra magnitude unit releases about 32 times more energy: an M5 is not "a bit stronger" than an M4 — it is a different league.

Energy estimated with the standard Gutenberg–Richter relation; an average lightning bolt ≈ 1 billion joules. Indicative values.

The race of the seismic waves

Two waves set off from the hypocentre: the faster P wave arrives first with a sharp jolt; the S wave carries the actual shaking.

P waves — the first sharp jolt (~6 km/s)S waves — the strongest shaking (~3.5 km/s)
t ≈ 83 s

Animation sped up ~16× compared to reality.

  • Corigliano-Rossano
    53 km from the epicentre
    first tremor in ~46 s
    main shaking in ~79 s
  • Cosenza
    78 km from the epicentre
    first tremor in ~47 s
    main shaking in ~81 s
  • Potenza
    81 km from the epicentre
    first tremor in ~47 s
    main shaking in ~81 s
  • Matera
    101 km from the epicentre
    first tremor in ~49 s
    main shaking in ~83 s

Theoretical times with average crustal speeds: real values vary with geology. The gap between P and S waves is what earthquake early-warning systems rely on.

How deep it was born

273 km
deep
31 times the height of Mount Everest

Being deep, it is felt less at the surface.

deeper than the area average (~20 km)

For the same magnitude, a shallow earthquake is felt much more than a deep one: the energy starts closer to the surface.

What kind of quake is this?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 2 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
16
last 30 days
3 before2 after
this quake
Strongest of the sequence2.3

How often does it happen here?

about every ~11 months

Within 50 km of this epicentre, a magnitude ≥ 3.5 earthquake has occurred on average this often: 13 events in the last 12 years of the INGV catalogue.

An average computed on the recent past: it tells how used this area is to shaking, not when the next quake will come — earthquakes cannot be predicted.

The great earthquakes in this area's history

Almost a thousand years of catalogues: the strongest documented events within ~50 km.

18577.1
Basilicata earthquake
16 December 1857 · 47 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19775.9
Golfo di Policastro earthquake
30 December 1977 · 46 km from here
18365.9
Appennino lucano earthquake
20 November 1836 · 28 km from here
IXDestructive: many buildings partly or fully collapse.
17085.6
Pollino earthquake
26 January 1708 · 11 km from here
VIII-IXDestructive: many buildings partly or fully collapse.

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Rimendiello-Mormanno

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 6.6between 1 and 12 km deep

Faults are mapped to build better and understand the territory: knowing them says nothing about when an earthquake will occur, which remains unpredictable. Source: DISS 3.3 (INGV, CC BY 4.0).

Other quakes in the area

2.3
1 km South-East of Grisolia
26 km South · 61 km
6 years ago
28 Jun 2020, 07:23
1.4
4 km East of Morano Calabro
17 km East · 9 km
6 years ago
15 Jun 2020, 10:37
1.8
5 km North-West of Morano Calabro
9 km South-East · 8 km
6 years ago
11 Jun 2020, 17:45
2.3
6 years ago
8 Jun 2020, 11:34
1.1
2 km North-West of Saracena
21 km South-East · 11 km
6 years ago
13 Jul 2020, 22:30

Data: INGV — National Institute of Geophysics and Volcanology (CC-BY 4.0)

Estimates computed by Meteare on INGV data (Gutenberg–Richter relation; Italian macroseismic intensity attenuation model).